Kdenlive/Manual/Effects/Alpha manipulation/Blue Screen: Difference between revisions

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== Blue Screen ==
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==== Chroma Key==== <!--T:1-->


[http://www.mltframework.org/bin/view/MLT/FilterFrei0r-bluescreen0r FilterFrei0r-bluescreen0r] <br>


This effect allows you to do Chroma Keying (Chroma key compositing/Green Screen) on Kdenlive. That is you can use the Blue Screen effect to generate alpha channel infomation allowing two video tracks to be combined using the [[Special:myLanguage/Kdenlive/Manual/Transitions/Composite|Composite transition]].
<!--T:3-->
This effect allows you to do Chroma Keying (also known as Green Screen or Blue Screen) in '''Kdenlive'''. Chroma keying is where you remove backgrounds of a similar colour. This effect is a very basic. For a more complication alpha manipulation/background removal effect, use  [[Special:myLanguage/Kdenlive/Manual/Effects/Alpha manipulation/Color Selection|Colour Selection]]


Note: Alternatively you can combine two video tracks together using the [[Special:myLanguage/Kdenlive/Manual/Transitions/screen|screen]] transition (if one of them is filmed on a black background).
<!--T:4-->
For black backgrounds, the [[Special:myLanguage/Kdenlive/Manual/Transitions/screen|screen]] transition is slightly more effective.  


=== Tutorial 1 ===
<!--T:29-->
Here are some video tutorials on how to use chroma key.


Youtube video on Chroma Keying which uses the Blue Screen effect
===== Basic Chroma Keying Tutorial ===== <!--T:30-->


{{#ev:youtube|DLHa6Gkv45Q}}
<!--T:36-->
1. Select the clip you want to chroma key in the timeline.


=== Tutorial 2 ===
<!--T:37-->
2. Search for "chroma key" in the effects tab, and drag it onto the properties tab.


Another video on chroma keying / green screen. This one also shows you how to use  [[Special:MyLanguage/Kdenlive/Manual/Effects/Alpha_manipulation/Rotoscoping|rotoscoping]] to remove stuff you do not want from out of your frame. It also means you don't need to fill your whole frame with the green screen either.
<!--T:38-->
3. Click on the button that looks like a water droplet, and then click on the background of the video. This will chroma key out the background.


Also uses
<!--T:39-->
4. Use the variance slider to control the amount of background chroma keyed out. This will require adjustment if your chroma key didn't immediately turn out perfect


* [[Special:MyLanguage/Kdenlive/Manual/Transitions/Composite|Composite Transition]].
* Crop and Transform>[[Special:MyLanguage/Kdenlive/Manual/Effects/Crop_and_transform/Pan_and_Zoom|Pan and Zoom effect]]
* Enhancment>[[Special:MyLanguage/Kdenlive/Manual/Effects/Enhancement/Sharpen|Sharpen Effect]]


{{#ev:youtube|_6gxHLCFhLQ}}
===== Video Tutorial ===== <!--T:40-->


=== Tutorial 3 ===
<!--T:41-->
{{#ev:youtube|bMwbffYIS40}}


Tutorial  showing how to use the "Blue screen" function and keyframes to animate one image moving over another in the KDEnlive video editor
===== See also ===== <!--T:23-->


Also uses
<!--T:24-->
See also [[Kdenlive/Manual/Effects/Alpha manipulation/Rotoscoping|Rotoscoping]] effect. Rotoscoping is where you manual draw a region, and everything outside/inside that region will disappear. This is useful for backgrounds with multiple different colours.


* [[Special:MyLanguage/Kdenlive/Manual/Transitions/Composite|Composite Transition]]
<!--T:35-->
* [[Special:MyLanguage/Kdenlive/Manual/Effects#Using_Keyframes_in_effects|Keyframes]]
See also [[Kdenlive/Manual/Effects/Misc/keysplillm0pup|Key Spill Mop Up]] effect in the Misc group. The Key Spill Mop Up effect can be used to improve the edges of the blue screen effect - when edge problems are caused by "keyspill". Keyspill is when the color of the screen used for colorkeying spills onto the subject due to light reflection.


{{#ev:youtube|M8hC5FbIzdE}}
<!--T:25-->
See also [[Kdenlive/Manual/Effects/Alpha_manipulation/Color_Selection|Colour Selection]] which also does color based alpha selection, but in a much more detailed fashion. Use it for less contrasting or more complex backgrounds.


=== Tutorial 4 ===
<!--T:27-->
 
Shows usage of the following effects: [[Special:MyLanguage/Kdenlive/Manual/Effects/Alpha_manipulation/Blue_Screen|blue screen]], [[Special:MyLanguage/Kdenlive/Manual/Effects/Alpha_manipulation/Alpha_operations|alpha operations]] - shrinkhard, [[Special:MyLanguage/Kdenlive/Manual/Effects/Enhancement/Denoiser|denoiser]] and [[Kdenlive/Manual/Effects/Misc/keysplillm0pup|keysplillm0pup]]
 
{{#ev:youtube|l43Hz7YEcYU}}
 
=== See also ===
 
See also [[Kdenlive/Manual/Effects/Misc/keysplillm0pup|keysplillm0pup]] effect in the Misc group. The keyspillm0pup effect can be used to improve the edges of the blue screen effect - when edge problems are caused by "keyspill". Keyspill is when the colour of the screen used for colourkeying spills onto the subject due to light reflection.
 
See also [[Kdenlive/Manual/Effects/Alpha_manipulation/Color_Selection|Color Selection]] which also does color based alpha selection.
 
see [http://www.kdenlive.org/forum/greenscreen-keying-edge this] thread for some discussion on chroma keying issues in Kdenlive
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Latest revision as of 20:32, 31 March 2019

Other languages:

Chroma Key

This effect allows you to do Chroma Keying (also known as Green Screen or Blue Screen) in Kdenlive. Chroma keying is where you remove backgrounds of a similar colour. This effect is a very basic. For a more complication alpha manipulation/background removal effect, use Colour Selection

For black backgrounds, the screen transition is slightly more effective.

Here are some video tutorials on how to use chroma key.

Basic Chroma Keying Tutorial

1. Select the clip you want to chroma key in the timeline.

2. Search for "chroma key" in the effects tab, and drag it onto the properties tab.

3. Click on the button that looks like a water droplet, and then click on the background of the video. This will chroma key out the background.

4. Use the variance slider to control the amount of background chroma keyed out. This will require adjustment if your chroma key didn't immediately turn out perfect


Video Tutorial

{{#ev:youtube|bMwbffYIS40}}

See also

See also Rotoscoping effect. Rotoscoping is where you manual draw a region, and everything outside/inside that region will disappear. This is useful for backgrounds with multiple different colours.

See also Key Spill Mop Up effect in the Misc group. The Key Spill Mop Up effect can be used to improve the edges of the blue screen effect - when edge problems are caused by "keyspill". Keyspill is when the color of the screen used for colorkeying spills onto the subject due to light reflection.

See also Colour Selection which also does color based alpha selection, but in a much more detailed fashion. Use it for less contrasting or more complex backgrounds.